The present invention relates to a controller and, in particular, to a controller for control of a power supply to a semiconductor device such as a CPU (Central Processing Unit).
A power supply device that can reduce overshoot/undershoot occurring when a power supply voltage is switched to another voltage and enables voltage switching at a higher speed is known.
For example, a power supply device according to Patent Document 1 (Japanese Published Unexamined Patent Application No. 2007-288974) operates as follows. In a transition state for increasing an output voltage, DD1 that is a DAC value in a register for DCDC, which is a register for a switching regulator 400, is supplied to a DAC 302 for LDO, instead of LD01 that is a DAC value in a register 201 for LD0, which is a register for a series regulator 300. The DAC 302 for LD0 of the series regulator 300 performs DAC operation, referring to DD1, a DAC value in the register 202 for DCDC.